Vertical-type centrifugal separation device

Abstract

[Problem] To prevent a separated liquid that has flowed into a collection chamber from overflowing. [Solution] The present invention is characterized by including: a cylindrical rotary cylinder in which a supply port for a liquid to be treated is formed in a lower side, and a discharge port for a separated liquid which has been centrifugally separated is formed in an upper side, the cylindrical rotary cylinder rotating around a vertical axis during the execution of centrifugal separation; a casing in which the cylindrical rotary cylinder is accommodated so as to be rotatable around the vertical axis; a collection cover that includes a bottom plate part in which a circular opening that has the cylindrical rotary cylinder inserted therein is formed, the collection cover forming a collection chamber which is for the separated liquid and which is in communication with the discharge port; and a separated-liquid discharge nozzle that is connected to the collection chamber, wherein the bottom plate part of the collection chamber inclines downward toward the outer periphery, and the edge of the circular opening of the bottom plate part is provided with a weir part including a vertical wall portion and a flange portion that protrudes from the upper end of the vertical wall portion toward the outer peripheral side of the bottom plate part.

Description

Vertical Centrifuge

[0001] The present invention relates to a vertical centrifugal separator for separating a liquid to be treated into solid and liquid.

[0002] A centrifugal separator is a device that can perform separation operations according to the purpose, such as solid-liquid separation, liquid-liquid separation, or solid-liquid-liquid separation, by applying centrifugal force to the liquid to be treated by supplying the liquid to a rotating bowl.

[0003] Patent Document 1 discloses a vertical centrifuge apparatus comprising: a cylindrical rotating shell having a supply port for a liquid to be treated formed at its lower side and a discharge port for a separated liquid obtained by centrifugation formed at its upper side, the cylindrical rotating shell rotating about a vertical axis during centrifugation; a casing in which the cylindrical rotating shell is housed so as to be rotatable about the vertical axis; a separated liquid collecting chamber having a circular opening formed in its bottom plate, the inner peripheral edge of which is located close to the outer peripheral surface of the cylindrical rotating shell, the separated liquid collecting chamber being arranged so as to surround the entire orbit of the discharge port of the cylindrical rotating shell; a separated liquid collecting cover having a separated liquid discharge nozzle connected to the collecting chamber and located at the upper side of the casing; and one or more straightening blades arranged on the back surface of the bottom plate of the collecting chamber, the surface of which facing the rotation axis of the cylindrical rotating shell being inclined inward, the surface of the straightening blade being inclined so that the end of the surface close to the rotation axis of the cylindrical rotating shell is lower than the end of the surface away from the rotation axis.

[0004] The vertical centrifugal separator is designed to suppress the effects of swirling airflow generated by the high-speed rotation of the cylindrical rotating cylinder, and to prevent mist of separated liquid from leaking from the collection cover.

[0005] Patent No. 5832789

[0006] However, with the configuration of Patent Document 1, there is a problem in that the separated liquid that flows into the collection chamber overflows and adheres to the back surface of the bottom plate of the collection cover, etc. A first object of the present invention is to prevent the separated liquid that flows into the collection chamber from overflowing. A second object of the present invention is to prevent the mist of separated liquid floating in the collection chamber from flowing out of the collection chamber toward the inside of the casing.

[0007] A first configuration of the vertical centrifuge according to the present invention is characterized in that: (1) a cylindrical rotating shell having a supply port for the liquid to be treated formed at its lower side and a discharge port for the centrifuged separated liquid formed at its upper side, the cylindrical rotating shell rotating about a vertical axis during centrifugation; a casing in which the cylindrical rotating shell is housed so as to be rotatable about the vertical axis; and a collecting cover including a bottom plate portion having a circular opening through which the cylindrical rotating shell is inserted, the collecting cover forming a collecting chamber for the separated liquid that communicates with the discharge port; and a separated liquid discharge nozzle connected to the collecting chamber, the bottom plate portion of the collecting chamber being inclined downward toward the outer periphery, and a dam portion including a vertical wall portion and a flange portion that protrudes from the upper end of the vertical wall portion toward the outer periphery of the bottom plate portion is provided at the edge of the circular opening of the bottom plate portion.

[0008] A second configuration of the vertical centrifugal separator according to the present invention is characterized in that (2) an airflow generating unit that generates an airflow from the casing toward the circular opening is provided in the vertical centrifugal separator of (1) above.

[0009] According to the first configuration of the present invention, it is possible to prevent the separated liquid that has flowed into the collection chamber from overflowing and adhering to the rear surface of the bottom plate of the collection cover, etc. (In other words, it is possible to achieve the first object.) According to the second configuration of the present invention, it is possible to further prevent the mist of separated liquid floating in the collection chamber from flowing out of the collection chamber toward the inside of the casing (In other words, it is possible to achieve the first and second objects.)

[0010] FIG. 1 is a front view of a vertical centrifugal separator (first embodiment); FIG. 2 is a side view of a vertical centrifugal separator (first embodiment); FIG. 3 is a plan view of a collection cover; FIG. 4 is an enlarged view of a portion of FIG. 1; FIG. 5 is an enlarged view of a portion of FIG. 4; FIG. 6 is an enlarged view of a portion of a vertical centrifugal separator of modified example 1, corresponding to FIG. 4; and FIG. 7 is an enlarged view of a portion of a vertical centrifugal separator (second embodiment), corresponding to FIG. 4.

[0011] First Embodiment Hereinafter, one embodiment of a vertical centrifugal separator according to the present invention will be described in detail with reference to the drawings. However, the technical scope of the present invention is not to be limited by the embodiment described below.

[0012] Fig. 1 is a front view of a vertical centrifugal separator according to this embodiment, with the casing partially cut away. Fig. 2 is a side view of the vertical centrifugal separator according to this embodiment, with a partial perspective view of the device. Fig. 3 is a plan view of a repair cover. This embodiment is a vertical centrifugal separator that achieves the first object described in the "Objects" section.

[0013] Referring to this figure, the vertical centrifugal separator 1 includes a bowl 2, which is a cylindrical rotating cylinder arranged in the vertical direction, a casing 3 as an exterior body that rotatably houses the bowl 2, a drive motor 4 as a drive device that generates power to rotate the bowl 2 around a vertical axis and perform centrifugation, and a support device 5 that supports these.

[0014] The casing 3 includes a casing body 31, and a collection cover 32 serving as an upper casing is detachably attached to the top of the casing body 31. The collection cover 32 receives the separated liquid discharged from the upper side of the bowl 2 by the action of centrifugal force during centrifugation, and guides the separated liquid toward a discharge nozzle 34.

[0015] A pipe (not shown) is detachably connected to the tip of the discharge nozzle 34, and this pipe is connected to a storage tank (not shown). Note that, although the bowl 2 of the vertical centrifugal separator 1 of this embodiment has a structure that separates the liquid to be treated into two phases, solid and liquid, the present invention is not limited to this.

[0016] Bowl 2 has a cylindrical body 21 with a hollow interior, with a supply port 22 for the liquid to be treated formed at the bottom and a separated liquid discharge port 23 for discharging the separated liquid formed at the top. A supply nozzle 24 for the liquid to be treated is inserted into supply port 22 formed at the bottom of bowl 2. Supply nozzle 24 is positioned away from the inner wall surface of bowl 2. This prevents contact between the inner wall surface of bowl 2 and supply nozzle 24 when bowl 2 rotates.

[0017] The liquid to be treated is delivered by a liquid delivery means (not shown), such as a pump, and is discharged from the tip of supply nozzle 24 and supplied into bowl 2. Although not shown, a blade member (for example, a three-wing blade member with three blades) is arranged inside bowl 2 to circumferentially divide the internal space of bowl 2.

[0018] Of the separated liquid and solids obtained by centrifugation, the separated liquid is continuously discharged from bowl 2, and the solids are accumulated in bowl 2. The accumulated solids are recovered after the vertical centrifugal separator 1 is stopped and the bowl 2 is removed from the casing 3. In other words, the vertical centrifugal separator 1 of this embodiment is a batch-type centrifugal separator.

[0019] The dimensions of bowl 2 are not particularly limited, but, as an example, the inner diameter falls within the range of 95 to 160 mm, and the length falls within the range of 457 to 730 mm. Bowl 2 is detachably connected to rotating shaft 26a of bearing assembly 26 by coupling nut 25, which serves as a detachment means. Bearing assembly 26 is connected to rotating pulley 42 of drive motor 4 through rotating belt 41. During centrifugation, bowl 2 is suspended and supported by connecting bowl 2 and bearing assembly 26, and rotates about a vertical axis by power generated by drive motor 4. On the other hand, when bowl 2 is to be removed from casing 3, the connection between bowl 2 and bearing assembly 26 is released by releasing the connection by coupling nut 25.

[0020] The collection cover 32 will be described in detail with reference to Figures 4 and 5. Figure 4 is an enlarged view of a portion of the vertical centrifugal separator, enlarging the area surrounded by the dotted line in Figure 1. Figure 5 is an enlarged view of a portion of the vertical centrifugal separator, enlarging the area surrounded by the dotted line in Figure 4. The collection cover 32 is composed of a bottom plate portion 32a, side plate portions 32b, and a top surface portion 32c, and functions as a collection chamber that collects the separated liquid obtained by centrifugation. The separated liquid discharge port 23 is formed at a position facing this collection chamber.

[0021] A circular opening 7 is formed in the center of the bottom plate portion 32a, and the tip (shaft) of the bowl 2 is inserted into this circular opening 7. The bottom plate portion 32a is tapered and slopes downward toward the outer periphery. By sloped the bottom plate portion 32a downward toward the outer periphery, a flow path can be formed that allows the separated liquid that flows in from the separated liquid discharge port 23 to flow toward the outer periphery. Because the circular opening 7 is formed in the center of the bottom plate portion 32a, the shape of the bottom plate portion 32a in a plan view is what is called a donut shape.

[0022] A dam portion 320 is disposed in a ring shape on the edge of the circular opening 7 of the bottom plate portion 32a. The dam portion 320 includes a vertical wall portion 321 and a flange portion 322 that protrudes from the upper end of the vertical wall portion 321 toward the outer periphery of the bottom plate portion 32. The vertical wall portion 321 and the flange portion 322 are integrally formed with each other. The vertical wall portion 321 extends in the longitudinal direction (i.e., the up-down direction) of the bowl 2. The flange portion 322 may protrude in a direction perpendicular to the longitudinal axis of the bowl 2 or in a direction inclined relative to the perpendicular direction. Providing the dam portion 320 on the edge of the circular opening 7 of the bottom plate portion 32a prevents the separated liquid from overflowing from the circular opening 7 and leaking behind the bottom plate portion 32a. Details of this effect will be described later.

[0023] The side plate portion 32b is formed to rise from the outer edge of the bottom plate portion 32a. A cutout portion is formed in the side plate portion 32b, and the discharge nozzle 34 is connected to this cutout portion. The bottom plate portion 32a and the side plate portion 32b can be formed integrally.

[0024] The top surface portion 32c is attached to the upper end of the side plate portion 32b and covers the upper opening of the collection cover 32. In other words, the top surface portion 32c is the upper lid of the collection cover 32. The inner edge of the top surface portion 32c has a flat shape extending in a direction perpendicular to the longitudinal axis of the bowl 2, and the outer edge has an inclined shape that slopes toward the upper end of the side plate portion 32b. In other words, the top surface portion 32c is formed in a stepped shape.

[0025] The inventors discovered that the separated liquid flowing into the collection chamber overflows the vertical wall portion 321 and leaks from the circular opening 7, and this leaked separated liquid (not in the form of a mist) adheres to the backside of the bottom plate portion 32a. It is presumed that a swirling flow is generated in the collection chamber due to the rotation of the bowl 2, and this swirling flow causes the separated liquid to spread along the bottom plate portion 32a and overflow the vertical wall portion 321. To solve this problem, the inventors discovered that providing a dam portion 320 consisting of the vertical wall portion 321 and a flange portion 322 on the edge of the circular opening 7 can prevent the separated liquid from overflowing. Whether the separated liquid has overflowed can be determined visually. After centrifugation, observing the backside of the bottom plate portion 32a and finding a thick layer of separated liquid adhering thereto indicates that the separated liquid has overflowed.

[0026] The liquid to be treated is not particularly limited, but may include, for example, baker's yeast, baking soda, ink, cocoa mass, a mixture of minced chicken bone and fish flakes, minced beef and pork, tea leaves, cross-linked acrylic polymer, collagen, saccharified grain (rice, barley, etc.), and vegetable pigment extract. The inventors have previously confirmed that when a separated liquid (e.g., ink pigment) with a surface tension lower than that of water flows into the collection chamber, the separated liquid tends to spread along the bottom plate portion 32a. That is, even with airflow control using straightening blades (see Patent Document 1), the spreading phenomenon along the bottom plate portion 32a cannot be suppressed for separated liquids with a surface tension lower than that of water. Therefore, they reexamined the means for solving the separated liquid leakage and discovered that providing a dam portion 320 on the edge of the circular opening 7 is an effective solution. Therefore, the vertical centrifuge device of the first embodiment is more suitable for separated liquids with a surface tension lower than that of water. However, it goes without saying that even if the separation liquid has a surface tension greater than that of water, the vertical wall portion 321 and the flange portion 322 work together to produce a dam effect.

[0027] Referring to FIG. 5 , the height dimension of the vertical wall portion 321 is defined as W, and the distance between the lower end of the separated liquid discharge port 23 and the upper end of the flange portion 322 is defined as Z. The height dimension W is preferably 10 mm or greater, and the distance Z is preferably 2 mm or greater. Increasing the height dimension W increases the amount of separated liquid received by the dam portion 320, thereby enhancing the dam effect. However, if the height dimension W is excessively large and the distance Z is reduced to less than 2 mm, the flow of separated liquid into the collection chamber may be hindered, potentially resulting in leakage of the separated liquid from the circular opening 7. For these reasons, the height dimension W is preferably 10 mm or greater, and the distance Z is preferably 2 mm or greater. The dimensions W and the distance Z can be changed by adjusting the inclination angle of the bottom plate portion 32a. For example, if the inclination angle is reduced during the design phase, the dimension W can be increased.

[0028] When the horizontal distance between vertical wall portion 321 and the outer peripheral surface of bowl 2 (hereinafter also referred to as clearance) is X, clearance X is preferably 2.0 mm or more and 3.5 mm or less. If clearance X is excessively small, bowl 2 and vertical wall portion 321 may come into contact during centrifugation. If clearance X is excessively large, the separated liquid may leak from circular opening 7 when it flows into the collection chamber from separated liquid discharge port 23.

[0029] When the horizontal length of the flange 322 (hereinafter also referred to as the protrusion length) is Y, the protrusion length Y is preferably 5 mm or more. If the protrusion length Y is too small, the dam effect of the flange 322 may be reduced. There is no particular upper limit to the protrusion length Y, but if the protrusion length Y is too long, the cleaning work of the collection cover 32 may become complicated, and the separated liquid may stagnate on the flange 322, preventing it from flowing into the collection chamber. Therefore, it is desirable to set the protrusion length Y to 15 mm or less.

[0030] Next, we will explain the operation (centrifugation) of the above-mentioned vertical centrifugal separator 1. First, the bowl 2 is rotated about its vertical axis, and the liquid to be treated is continuously supplied into the bowl 2 through the supply nozzle 24. The centrifugal force of the bowl 2 is preferably 10,000 G or more, and more preferably 20,000 G or more.

[0031] The liquid to be treated supplied to bowl 2 is separated into two phases, solids and separated liquid, by centrifugal force and the difference in specific gravity. The solids accumulate on the inner circumferential surface of bowl 2, and the separated liquid is discharged from separated liquid discharge port 23 toward the collection chamber.

[0032] The separated liquid that flows into the collection chamber is discharged from the discharge nozzle 34 along the tapered surface of the bottom plate portion 32a, but some of the separated liquid remains in the collection chamber and spreads along the bottom plate portion 32a due to the action of the swirling flow. At this time, the separated liquid is blocked by the dam portion 320, which is composed of the vertical wall portion 321 and the flange portion 322, preventing the separated liquid from overflowing from the circular opening 7. In the configuration of this embodiment, although the amount may be small, a mist of separated liquid may leak from the circular opening 7 and adhere to the wall surface of the casing main body 31. Whether or not a mist of separated liquid has leaked can be determined visually. When the separated liquid is scattered in dots on the wall surface of the casing main body 31, it can be determined that a mist of separated liquid has leaked.

[0033] (Variation 1) In the above-described embodiment, the dam portion 320 is configured by integrally forming the vertical wall portion 321 and the flange portion 322. However, the present invention is not limited to this. The vertical wall portion 321 and the flange portion 322 may be separate bodies. FIG. 6 is a cross-sectional view of a portion of a vertical centrifugal separator according to this variation, corresponding to FIG. 4 . The dam portion 320 includes the vertical wall portion 321 and a ring-shaped flange portion 323. The ring-shaped flange portion 323 includes a flange main body 323a and leg portions 323b, which are integrally formed. The leg portions 323b are ring-shaped and are in pressure contact with the outer peripheral surface of the vertical wall portion 321. The flange main body 323a is provided at the upper end of the leg portions 323b and protrudes toward the outer peripheral side of the bottom plate portion 32a. The vertical wall portion 321 and the ring-shaped flange portion 323 of this variation also provide the above-described dam effect.

[0034] (Variation 2) In the above-described embodiment, the collection chamber formed by the collection cover 32 has a single stage, but the present invention is not limited to this and may have a two-stage structure (see, for example, Patent Document 1). In this case, for example, the lower stage may be the heavy liquid collection chamber and the upper stage may be the light liquid collection chamber, and a dam portion may be provided on the edge of the circular opening in the bottom plate portion of at least one of the heavy liquid collection chamber and the light liquid collection chamber.

[0035] Second Embodiment FIG. 7 is an enlarged view of a portion of a vertical centrifugal separator according to this embodiment, corresponding to FIG. 4 . The direction of the airflow generated by the flow-straightening blades is schematically indicated by dashed arrows. This embodiment relates to a vertical centrifugal separator that achieves both the first and second objectives described in the "Problems" section. Separate liquid flowing into the collection chamber collides with the inner wall of the collection cover 32, causing a portion of the separated liquid to turn into mist. Although only a small amount, the mist-like separated liquid may be drawn into the swirling flow in the collection chamber and leak from the circular opening 7 toward the casing body 31. This problem is described in Patent Document 1, paragraphs 0007 and 0008, and therefore will not be described in detail here.

[0036] Referring to FIG. 7 , a plurality of straightening blades 51 (corresponding to “airflow generating units”) are disposed on the rear surface of the bottom plate unit 32 a. By tilting the surfaces of the straightening blades 51 inward, an airflow can be generated that causes the air drawn into the casing body 31 from the supply nozzle 24 to flow toward the circular opening 7, i.e., an upward airflow, during operation of the vertical centrifugal separator. The structure of the straightening blades 51 that achieves this effect is a conventional technique, as disclosed in, for example, Patent Document 1, and therefore a detailed description thereof will be omitted. By providing the straightening blades 51 in addition to the dam unit 320, it is possible to prevent leakage of the separated liquid due to overflow while also preventing leakage of the mist-like separated liquid due to the drawing in of the swirling flow.

[0037] In this embodiment, the airflow generating unit is realized by the flow straightening blades 51, but the present invention is not limited to this. For example, an upward airflow toward the circular opening 7 may be forcibly generated by blowing air into the casing main body 31 from the supply nozzle 24 using a blower or other air sending means (corresponding to the "airflow generating unit").

[0038] Here, by setting the dimension W to 10 mm or more, the air generated by the airflow generating section can be taken in approximately evenly from the entire circumference of the circular opening 7. Furthermore, by setting the protruding length Y of the flange portion 322 to 5 mm or more, a portion of the air taken in through the circular opening 7 can be made to flow along the flange portion 322. As a result, leakage of the mist-like separation liquid can be more effectively prevented. Note that the other dimensional conditions of W, X, Y, and Z described in the first embodiment can also be applied to this embodiment. Needless to say, the configurations of the above-mentioned modifications 1 and 2 can also be applied to this embodiment.

[0039] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various substitutions, modifications, changes, etc. in form and detail can be made therein without departing from the spirit and scope of the present invention as defined by the claims. Therefore, the scope of the present invention should not be limited to the above-described embodiments and accompanying drawings, but should be determined based on the claims and their equivalents.

[0040] DESCRIPTION OF SYMBOLS 1 Vertical centrifugal separator 2 Bowl 3 Casing 23 Separated liquid outlet 32 ​​Collection cover 32a Bottom plate 320 Weir 321 Vertical wall 322 Flange 51 Flow straightening blade 7 Circular opening

Claims

1. A vertical centrifuge comprising: a cylindrical rotating shell having a supply port for a liquid to be treated formed at its lower side and a discharge port for a separated liquid obtained by centrifugal separation formed at its upper side, the cylindrical rotating shell rotating about a vertical axis during centrifugation; a casing in which the cylindrical rotating shell is housed so as to be rotatable about the vertical axis; a collection cover including a bottom plate portion having a circular opening through which the cylindrical rotating shell is inserted, the collection cover forming a collection chamber for the separated liquid communicating with the discharge port; and a discharge nozzle for the separated liquid connected to the collection chamber, wherein the bottom plate portion of the collection chamber is inclined downward toward the outer periphery, and a dam portion including a vertical wall portion and a flange portion protruding from an upper end of the vertical wall portion toward the outer periphery of the bottom plate portion is provided at the edge of the circular opening of the bottom plate portion.

2. The vertical centrifugal separator according to claim 1, characterized in that, when the dimension of the vertical wall portion in the up-down direction is defined as W and the distance between the lower end of the discharge port and the upper end of the flange portion is defined as Z, W is 10 mm or more and Z is 2 mm or more.

3. The vertical centrifugal separator according to claim 1 or 2, characterized in that, when the protruding length of the flange portion is defined as Y, Y is 5 mm or more.

4. The vertical centrifugal separator according to claim 1 or 2, characterized in that the surface tension of the separation liquid is lower than that of water.

5. The vertical centrifugal separator according to claim 3, wherein the surface tension of the separation liquid is lower than that of water.

6. The vertical centrifugal separator according to claim 1 or 2, further comprising an airflow generating unit that generates an airflow from the casing toward the circular opening when the vertical centrifugal separator is in operation.

7. The vertical centrifugal separator according to claim 3, further comprising an airflow generating unit that generates an airflow from the casing toward the circular opening when the vertical centrifugal separator is in operation.

8. The vertical centrifugal separator according to claim 4, further comprising an airflow generating unit that generates an airflow from the casing toward the circular opening when the vertical centrifugal separator is in operation.

9. The vertical centrifugal separator according to claim 5, further comprising an airflow generating unit that generates an airflow from the casing toward the circular opening when the vertical centrifugal separator is in operation.

Images